Assessing onset of treatment benefit in depression and anxiety: conceptual considerations.

Objective: Methods for characterizing the onset of treatment benefit in major depressive disorder and generalized anxiety disorder have been studied for some time, yet there is no universal agreement as to the best approaches. Our purpose is to summarize the conceptual framework underlying modern methods for characterizing onset and detailed approaches for which there is consensus from the perspective of a clinician, clinical researcher, and statistician. Possible alternatives to unresolved issues are discussed.